The goal of this training program is to train biostatisticians to take a leadership role in developing new interdisciplinary scientific research. This will be achieved by providing rigorous training in the disciplines of statistics and microbiology, and also providing interdisciplinary training in bioinformatics. This training program will provide a structure that will strengthen existing collaborations, and train a new generation of biostatisticians to advance biomedical and clinical research. It will support PhD training in biostatistical theory and associated evolving statistical methodologies related to basic biomedical research including microbiology, infectious diseases and bioinformatics. Key to our approach is that trainees in the PhD program in Biostatistics, or in a concentration of the PhD program in Statistics which specializes in biostatistics, will be required to undertake: 1) a common core of course work in general microbiology in year 1, including a laboratory component;2) course work with computer laboratory in statistical methods for bioinformatics and a seminar in statistics in microbiology, in either year 1 or year 2;and 3) two summer laboratory rotations. The laboratory rotation at the end of year 1 will be in a microbiology laboratory, and in year 2 will be either in the same microbiology laboratory, in a different microbiology laboratory, or in a bioinformatics computer laboratory, or in a genomics laboratory combining computational biology and bioinformatics with biology. The choice of rotations will depend on the trainee's evolving interests. Additional laboratory rotations and courses in microbiology, infectious diseases and bioinformatics are available and rotations and co-mentors have been identified in these areas. Graduate students and postdoctoral trainees in Microbiology will be involved as peer-mentors and laboratory mentors. PhD students in microbiology, or a closely related program, will be eligible for 1 year of support to pursue training in biostatistics to further their thesis research. For statistics and biostatistics PhD trainees, thesis advisors will be from the Department of Biostatistics and the Department of Statistics &Actuarial Science, and co-advisors will be from the Department of Microbiology, Division of Infectious Diseases, Center for Bioinformatics and Computational Biology, and the Center for Comparative Genomics. The 25 core faculty members consist of 16 statistical scientists and 9 biological scientists who are all firmly committed to this collaboration and program. At least 2 new trainees will be recruited in each of the 5 years of the grant.